Electrocardiogram

Question 1

What is an 1st degree AV block?

Answer 1

Lengthened delay between atrial and ventricular depolarization; PR interval > .2 seconds

Question 2

What are the 2 types of 2nd degree AV block?

Answer 2

Wenckebach and Mobitz

Question 3

Describe Wenckebach

Answer 3

Each P wave and its associated QRS get progressively farther apart in successive cycles until the last doesn’t make it through.

Question 4

Describe Mobitz

Answer 4

Series of cycles consisting of one normal cycle preceeded by a series of paced P-waves that don’t conduct; A block of the purkinje fibers
P-waves are never premature

Question 5

What are the EKG findings of Mobitz?

Answer 5

Widened QRS with normal PR interval

Question 6

Describe a 3rd degree AV block

Answer 6

No conduction of atrial stimuli to the ventricles.

Look for AV dissociation and Escape rhythms.

Question 7

Discuss Bundle Branch Blocks

Answer 7

Widened QRS > .12s; ‘Rabbit ears’ in V1 or V2 = RBBB

‘Rabbit ears’ in V5 or V6 = LBBB

Question 8

Discuss the EKG findings of an anterior hemiblock

Answer 8

1. Left Axis Deviation
2. Q1S3; Significant Q waves in Lead 1, Deep S wave in Lead 3
3. Occlusion of Anterior Descending Artery

Question 9

Discuss the EKG findings of a posterior hemiblock

Answer 9

1. Right Axis Deviation

2. Q3S1

Question 10

Discuss the EKG findings of Atrial Enlargement

Answer 10

Diphasic P-wave in V1;
Large initial component = RAE
Large terminal component = LAE

Question 11

Discuss the EKG of Right Ventricular Hypertrophy

Answer 11

1. Large R wave in V1
2. S wave is smaller than R wave in V1
3. Right axis deviation
4. R wave gets progressively smaller in leads V1,2,3,4

Question 12

Discuss the EKG of Left Ventricular Hypertrophy

Answer 12

1. Exaggerated amplitude of QRS in all chest leads.
2. Large S in V1
3. Large R in V5
4. Inverted T wave with gradual down slope and sharp return

Question 13

Discuss the EKG findings of Ischemia

Answer 13

Symmetrical inverted T wave; Especially in V2-V6

Question 14

Discuss the EKG findings of Injury

Answer 14

ST segment elevation; Indicates Acute infarction

Question 15

Discuss the EKG findings of Pericarditis

Answer 15

Elevated and flat/concave ST segment

Question 16

What does ST segment depression indicate?

Answer 16

1. Subendocardial Infarction: An infarct that doesn’t extend through entire heart wall.
2. Digitalis

Question 17

Discuss the EKG findings of Necrosis

Answer 17

Significant Q waves; At least 1 small box wide OR 1/3 entire QRS amplitude

Question 18

Discuss the EKG findings of an Anterior wall infarction

Answer 18

1. Significant Q waves in V1-V4
   If isolated in V1-V2= antero-septal infarction
   If isolated in V3-V4= antero-lateral infarction
2. Occlusion of Anterior Descending branch of the LCA

Question 19

Discuss the EKG finding of a Lateral Infarction

Answer 19

1. Q waves in Leads 1 and AVL

2. Occlusion of Circumflex branch of LCA

Question 20

Discuss the EKG findings of an inferior wall infarction

Answer 20

1. Q waves in Leads 2,3 and AVF

Question 21

Discuss the EKG findings of a posterior wall infarction

Answer 21

1. Large R waves in V1-V3.
2. ST depression in V1 or V2
3. Occlusion of Right Coronary Artery

Question 22

Why is a posterior wall infarction (Occlusion of RCA) so dangerous?

Answer 22

RCA supplies blood to the SA node, AV node and Bundle of His

Question 23

Differentiate between Hyperkalemia and Hypokalemia on an EKG

Answer 23

Hyperkalemia: P-wave flattens and widens, QRS widens, T-wave becomes peaked
Hypokalemia: T wave becomes flat or inverted and a U-wave appears.

Question 24

Differentiate Wandering Pacemaker from Multifocal Atrial Tachycardia

Answer 24

Both have P’ but with Wandering pacemaker the atrial rate is < 100.

Question 25

Differentiate WPW syndrome from LGL syndrome

Answer 25

WPW: Delta waves = Premature deplorization of a portion of the ventricles
LGL: No PR interval = No AV delay. P-waves are adjacent to their QRS’